St. Charles County, Mo (KSDK) -- After five weekday mornings of lane closures on the Blanchette Bridge, the Missouri Department of Transportation is continuing to encourage drivers to use alternate routes.

Interstate 70 on the Blanchette Bridge was reduced from 10 lanes to six.

Drivers are advised to use 370 and 364 as alternate routes during rush hours.

MoDOT Community Relations Coordinator Linda Wilson Horn said the number of cars using I-70 during the morning and evening rush has increased slightly each day this week. Morning backups have been occurring eastbound I-70 at Route 94, while evening backups have been occurring westbound I-70 between I-270 and Earth City.

MoDOT said there is a chance of back-ups Friday night if drivers do not use alternate routes.

"If motorists continue to come back to I-70 during rush hours, we are right on the tipping point of having more severe backups," said MoDOT St. Louis Assistant District Engineer Bill Schnell. "Friday night is especially busy on westbound I-70 and motorists should be prepared for stopped traffic on the bridge to the Fifth Street exit."

Along with the I-70 lane closures, the ramp from northbound Fifth Street to eastbound I-70 remains closed until Fall 2013. MoDOT is performing $63 million in major rehabilitation to the 54-year-old westbound bridge. For more information on the project, visit www.modot.org/blanchettebridge.